All patients were treated with fractionated RT to the CSA (3520 cGy to CSA with additional boost to the supratentorial tumor of 20 Gy).

Results of HIT trial:

Immediate RT followed by maintenance chemotherapy was better than delaying RT with pre-RT chemotherapy (with an increased rate of early progression 22% in the pre-chemo RT group versus 4% in the immediate RT group).

Dose and volume of RT significant prognostic factor:

Progression free survival decreased if there were major protocol violations in the way RT as given23

Protocol violations were defined as:

CSA RT dose less than 35 Gy

Local tumor boost dose less than 54 Gy

No CSA RT was given

No RT was performed

Effectiveness of RT16:

Study of 15 children under18 years old with non-pineal supratentorial PNETs

Initial treatment with surgery and chemotherapy was given to all patients

RT delivered as follows:

Up front (initial) RT in 5 patients

RT given at time of progression in 5 patients

No RT in 5 patients

All patients receiving upfront RT were alive without any evidence of disease at a follow up averaging 4 years

PTV = Institutionally defined margin for daily set up error. Usually 0.3 cm to 0.5 cm (but may be more for craniospinal RT)

The recommended dose is 36 Gy in 180 cGy fractions

Boost to primary tumor:

Primary site:

GTV includes all gross residual tumor and/or the walls of the resection cavity at the primary site based on initial imaging (contrast enhanced MR scan) showing extent of original tumor prior to surgery and should also include residual disease after surgery.

CTV = GTV + margin for microscopic residual disease

CTV = GTV + 1 cm

Margin may be reduced to 0.5 cm to allow for sparing of critical structures (e.g. total dose to the optic chiasm and both optic nerves should not exceed 50.4 Gy).

PTV = 0.3 cm to 0.5 cm margin around the CTV to account for day-to-day set up variation.

The recommended total dose to a supratentorial primary tumor is either 54 Gy or 55.8 Gy in 180 cGy (this includes both the CSA RT as well as the boost).

Metastatic Deposits:

Patients with M3 disease (spinal metastatic deposits visible on MR scan) should be given boosts to metastatic deposits.